The Ebon Blade - colloquially known as the "Ladies of the Ebon Blade" by some - are a secretive but fairly notorious band of female ESPers who undergo rigorous, brutal training to make them into skilled and ruthless assassins and interrogators. Mostly known to the criminal underworld and to various intelligence agencies (and other ESPer organizations), the Ebon Blade are both despised and feared; despised for the things they do (especially with recruitment) and feared for those very same actions.
Virtually all Ebon Blade recruits come into the group by way of abduction. Parents and family who resist are killed summarily or taken prisoner as well, so that their suffering can be used to help in the process of destroying any tendencies toward compassion and mercy in the recruited girls. After abduction they are taken to the Ebon Blade's stronghold, a place called the Ebon Tower that almost none outside the Blade know the location of (those who do know would be Marked immediately upon the Blade discovering it). There they are first brutalized constantly and encouraged to brutalize each other. Any family members taken as prisoners are tortured to death, slowly, as the recruit is forced to watch. Sometimes the recruit is even forced to participate as part of her own training.
After months of suffering the new recruits inevitably break down, allowing the Ebon Blade to rebuild them as remorseless agents of pain and death. Combat arts, including various forms of martial arts and ESPer combat techniques, are taught to them, as are the specifics of weapons use, knowledge of the anatomy of sentient races, and finally, an education in the arts of inflicting pain (which frequently involves "playing" - a euphemism for sexually-charged torture - with younger recruits or with non-ESPer prisoners abducted for just this purpose), all to aid them in their tasks of assassination and interrogation. The end result is almost always the same - a highly-trained and sadistic killer without a shred of mercy or compassion left within her, one who will inevitably continue the terrible cycle by aiding in the abduction and training of other young girls in the future.
There have been reports and scraps of information that hint at the existance of the Ebon Blade for a millennium. Their activities picked up in the late 30th Century, leading many to speculate they were either founded or taken over by traumatized ESPers freed from Dilgrud experimentation camps or from refugees fleeing from the Center of Special Abilities's cruel ESPer testing grounds. A number of intelligence agencies believe them responsible for various high profile assassinations over the years while it is known that criminal organizations hire them to help deal with leaks and informants. Humanitarian organizations and others active in the various frontier and shoal space regions have also dealt with them, primarily as opponents, as the Ebon Blade's recruitment capability relies primarily upon abducting young girl ESPers (usually of 12-16 years of age) and such is much easier to do on minor worlds than in worlds under the rule of a modern, sophisticated interstellar state.